Activated Carbon Odor Killer Filter for RV's and Boats

If you have an RV or a boat, you likely have a holding tank for sewage. If you have a holding tank, you have a problem with odor.  Right? It's the price we have to pay for having some of the necessary comforts of home in our RV or boat.

These holding tanks all have a vent, or they would explode, and if you thought odor was a problem.... 
Activated carbon, available as aquarium filter media, will remove the odor from vent gas.

I built a home made odor killer for the holding tank on our boat which solved the problem.

I used these parts:

2" PVC pipe, 24" long
2" fittings for each end, the glue-on type. These fittings need to reduce down to a size where you can slide a length of clear vinyl tube over it. So, I used fittings that reduced town to a short length of 3/4" PVC pipe so that I could slide 1" vynl hose over it tightly.
1" vinyl tube
Activated carbon that can be bought at a pet store
Fine screen, like window screen, of fine wire screen.

You will need to cut the screen into two  2" (or so) circles and glue them into the 2" fittings. This will keep the activated carbon inside the filter.

One fitting, with the screen inside it, is glued permanently to one end of the 2" pipe. In this photo you can see where the fitting reduces down to the 3/4" nipple extension.

Fill the tube FULL of the activated carbon. If you don't have enough carbon, cut the pipe shorter! The pipe must be full.
When I took this photo with my old cheap cell phone, you could see the carbon up to the top of the pipe.

Tape the other fitting on so you can remove it later for replacing the activatd carbon. Use duct tape, of course.
Use the vinyl tube to make connections to tank vent and outside exit vent. You might want to use hose clamps.
The 1" vinly tubing (hose) is the size that fit the pipe fittings on my boat. Your sizes may be different.